This study is a review of literature on the role of 3 dimensional radiation therapy in the management of mediastinal tumors. Moreover, special comparison has been made with classical 2 dimensional radiation therapy of the same anatomical area as regards dose escalation and toxicity. Although, the incidence of mediastinal tumors has increased in the last 10 years, it is still categorized as rare tumors in the all WHO and other international neoplasms classifications. In NEMROCK it is about 0.49% of the total registered cases in the last 10 years between 1999 – 2009. The anatomical location of the mediastinum and the necessity of using radiation therapy in treatment of mediastinal tumors, made many normal tissues to be significantly considered as risk organs such as the spinal cord, lungs, and the heart.Radiation therapy is used on the base of definitive, preoperative, adjuvant orpalliative issues, depending on the histopatological classification of the mediastinal tumors, the different stages of patient at presentation and the medical condition of the patients. The advancement in the computed programmes with modern imaging devices, facilitate the use of 3DRT (3D-CRT & IMRT) in treatment of mediastinal tumors to overcome obstacles in conventional radiation therapy and improvement of the results. Three DRT gives the possibility of radiation dose escalation with improvement of the therapeutic ratio and less toxicity to the pulmonary tissues and the heart. In addition to that, IMRT technique makes great breakthrough in form ofpossibility of re-irradiation or radiation to the large volumes mass in themediastinum.